/*
I've tried multiple iterations - edits of "private" and "static" out of line 3 without success. The Silver Stripe package was installed with WebMatrix 3. What is line 3 doing to crash the dev/build?
*/

Thank you Fried Buffalo! Unfortunately, changing the declaration to public made no difference - see attachment.

By default isn't the system is in"dev" mode automatically when running /dev/build?
And the line in _ss_environment.php - define('SS_ENVIRONMENT_TYPE', 'dev') - sets the site in dev mode at initial installation?
Yet the error reporting as shown in the attached file is insufficient [for me].

Hmm... a direct copy+paste and changing the declaration builds successfully on my end (using 3.1). Are you also using 3.x?

The configs seem to be setup correctly so far, although I'd also ensure PHP's display_errors and display_startup_errors are enabled to ensure the E_ALL is being read.

The screenshots show ArticlePage is building successfully, so I doubt there's a missing/typo'd class which is normally the source of my dev/build fails.

SilverStripe has a rough initial learning curve (I also hit a brick wall at tutorial 2 due to the beginners tutorial/docs having not caught up to 3.1 yet) but there's definitely rewards in the form of a focused, extensible API and rapid development speed if you stick to it.